Disease Knowledge in People With FAP Family History Differs From Those With Treatable Diseases

People at risk for familial amyloid polyneuropathy (FAP) caused by mutations in the TTR gene have different levels of knowledge about their disease than people at risk of treatable genetic conditions, according to researchers at the European University of Lisbon.

This is, however, not exclusive to people with a family history of FAP, as researchers showed that people at risk for other late-onset neurological illnesses like Huntington’s disease and Machado-Joseph disease shared certain knowledge features with people at risk of FAP.

The study, “Subjects at Risk for Genetic Late-Onset Neurological Diseases: Objective Knowledge,” appeared in the journal Public Health Genomics.

The research team figured that people with these more severe diseases will have known different things about their condition than those who risk a disease like hereditary hemochromatosis (HH).

The team chose this comparison for several reasons. FAP and other neurological conditions are genetically inherited in a dominant manner. This means that only one mutated gene copy is needed to develop the disease. And whoever carries the mutated gene will develop the incurable condition.

By contrast, HH is not severe, and with early detection and the right treatment, patients can live a full life without symptoms. It is also inherited in a recessive manner, meaning that both gene copies need to carry the mutation for the disease to appear.

To explore differences in knowledge, researchers recruited 213 people at risk for a late onset neurological disease (LOND), 179 of which were at risk for FAP. They had opted to undergo genetic testing to see if they carried a faulty gene.

Before the test, researchers let them answer the open-ended question: “What do you know about this disease?”

They compared the answers to those of 31 individuals at risk for HH. All participants were older than 17 years.

It turned out that patients with FAP and other neurological conditions most frequently gave disease references in the form of disease characteristics, symptoms, treatments and consequences. They also frequently commented how much — or little — they knew about the disease or mentioned their affected family members or spoke in metaphors.

People at risk of FAP and the other neurological conditions more often gave references, spoke about family members or provided metaphors than those at risk of HH, who were more likely to give quantitative answers, speaking of how much, or little they knew.

This difference, researchers said, was caused by FAP patients’ inability to control their disease. This causes a need to give the disease meaning, which they do by using metaphors, they argued. As such, “genetic counseling protocols of subjects at risk for LOND should include questions concerning family knowledge and disease experience,” researchers concluded.